The present invention relates generally to edge card connectors, and more particularly, to an edge card connector having an edge card alignment mechanism which assists in and maintains the alignment of the edge card with terminals in the card slot of a connector during insertion.
Circuit, or edge card, connectors have been developed for computers to provide connections between main computer printed circuit boards, commonly referred to in the art as "mother" boards, and secondary electronic circuits contained on smaller printed circuit boards, commonly referred to in the art as "daughter" boards. These secondary circuits may be added to computers or other electronic devices during or after the initial manufacture thereof to enhance, improve or alter the performance thereof. They may be added by a professional electronic technician or a relatively unskilled computer user.
Space on the mother boards of computers is at a premium. Consumers prefer smaller electronic devices and, therefore, when assembly components, such as daughter boards, are spaced closer together on the mother board, the overall device may become more compact and more desirable to the consumer.
A number of different known connectors are intended for permanent installation on a computer mother board and provide a connection between circuitry on the mother board and various daughter boards. Daughter boards are often descriptively referred to in the art as "edge cards," because typically one edge of the card contains a plurality of electrical contacts or contact pads that extend laterally along the edge and provide the point of operative electrical connection between the edge card circuitry and the mother board circuitry. The bottom edge of the edge card is inserted into a card slot formed in the connector. The connector card slot includes a plurality of electrical contacts which lie in opposition to the edge card contacts. The connector contacts may extend down from the connector slot through the connector body and terminate in tail portions which are aligned with a series of openings on the mother board. The tails are received in the mother board openings and may be soldered to form electrically conductive connections between the mother board and the edge card connector. In the alternative, the tails may be surface mounted to the mother board as is known in the industry.
There are many edge card connectors existent in the art. A number of these connectors include mechanisms which secure, or "latch," the edge card in place within the connector after the insertion thereof in order to retain the edge card in a connective relationship in the connector. Other edge card connectors include ejection mechanisms which permit the user to easily eject the edge card from the connector slot after insertion to enable the computer user to easily remove the edge card from the connector. Still other edge card connectors include a combined latch-eject mechanism which performs both the latch and eject functions.
Alignment of the edge card contacts with the contact terminals of the connector card slot is extremely important. If an edge card is inserted into a connector card slot in a misaligned fashion, the contact adjacent the card slot may not establish a reliable connection with the contacts of the edge card or may result in incorrect connection between circuits on the edge card and the mother board. Positioning the edge card in the card slot after it has been inserted into the card slot may result in damage to the contact terminals in the card slot.
However, in an effort to further reduce the size of electronic components, connectors have been reduced in size and the pitch of connectors, i.e., the spacing between contact terminals, has become smaller. With a smaller pitch, the alignment of the edge card within the connector card slot becomes more critical. Where a small pitch is involved, misalignment during insertion of the edge card may result in damage to some of the circuitry on either the edge card or on the mother board on which the edge card connectors is mounted. In addition, it is sometimes desirable to permit edge cards to be inserted into the card slot while the connector is "hot." In other words, it may be desirable to be able to insert the edge card without turning off the power to the electronic component. At such time, it is especially important that each of the contacts pads of the edge card be properly aligned with the appropriate contacts of the connector in order to prevent any damage to fragile electronic circuits.
Some edge card connectors may include either projections formed within the card slot near the ends or in the center thereof which assist in orienting the edge card into its proper location in the card slot during insertion of the edge card into the edge card connector. Other connectors may incorporate alignment guides integrally molded as part of the connector housing which extend upwardly in the form of posts that define opposite ends of the card slot. These alignment guides are generally long and narrow members and may present problems when molding the housing from certain materials. In addition, some high temperature plastic materials from which the housings are molded are not particularly wear-resistant and repeated insertions and withdrawals of edge cards into and out of the card slot may cause substantial wear on the alignment guides and eventually may result in misalignment of the card.
Accordingly, a need exists for an edge card connector which incorporates an alignment mechanism into a latch/eject member. Such a structure is lacking in the art.
U.S. Pat. No. 4,898,540, issued Feb. 6, 1990, includes a rotatable latch/eject member that is rotatably mounted to an end of the edge card connector and includes a lower eject or push-up portion which engages the bottom part of a polarizing notch of an edge card connector. The lower portion provides a surface of the latch/eject member which bears against the edge card to provide a means for ejecting the edge card from the card slot.
U.S. Pat. No. 5,163,847 issued Nov. 17, 1992 to the assignee of the present application, describes an edge card connector assembly in which the card connector includes two rotatable latch members disposed at opposite ends of the connector and each of the latch/eject members having a pair of spaced projections extending therefrom which interengage a pair of recesses in the adjacent side edges of the circuit card. These projections move in serial order into and out of the recesses in response to pivoting of the latch/eject member. However, each of the latch/eject members of this connector assembly must be maintained in alignment in their open position at their maximum rotation to permit insertion of the circuit card. The circuit card or the edge card is not insertable at any angle of operation. This required alignment adds to the complexity of operation of such a connector.
Lastly, U.S. Pat. No. 1,167,517, issued Dec. 1, 1992 describes a latch/eject member for an edge card connector which includes an ear portion formed on the latch/eject member which extends into a polarizing slot of a edge card in order to act as a guide for insertion of the edge card. Although it identifies the proper orientation of the edge card within the connector card slot, it does so only with respect to the polarizing slot and only assists the user improperly placing the edge card in the proper orientation to be received by the housing card slot. The ear portion does not laterally align the card edges with respect to the card slot.
Accordingly, a need for an edge card connector having an alignment mechanism incorporated into a latch/eject member exists which is simple to operate and which effectively aligns the edge card at any position of the latch/eject member during insertion thereof.